[Intel-gfx] [PATCH 08/10] drm/i915/gtt: Make swapping the pd entry generic

[Chris Wilson]

Quoting Mika Kuoppala (2019-06-14 17:43:48)
> Swapping a pd entry is same across the page directories, if
> we succeed we need to increment the count and write the phys page
> entry. Make a common function for it.
> 
> v2: inline (Chris)
> 
> Signed-off-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c | 42 +++++++++++++++++++----------
>  1 file changed, 28 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 8baceb9f64c5..0fffa0608ea5 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -754,6 +754,28 @@ static void __set_pd_entry(struct i915_page_directory * const pd,
>                        gen8_pde_encode(px_dma(to), I915_CACHE_LLC));    \
>  })
>  
> +static inline void *
> +__swap_pd_entry(struct i915_page_directory * const pd,
> +               const unsigned short pde,

These can be the struct px_dma base type (or whatever that was called)

> +               void * const old_val,
> +               void * const new_val,
> +               const dma_addr_t daddr,
> +               u64 (*encode)(const dma_addr_t, const enum i915_cache_level))
> +{
> +       void * const old = cmpxchg(&pd->entry[pde], old_val, new_val);
> +
> +       if (likely(old == old_val)) {
> +               atomic_inc(&pd->used);
> +               if (likely(pd_has_phys_page(pd)))
> +                       __set_pd_entry(pd, pde, encode(daddr, I915_CACHE_LLC));

and then s/daddr/px_dma(to))/
?

> +       }
> +
> +       return old;
> +}
> +
> +#define swap_pd_entry(pd, pde, old, to) \
> +       __swap_pd_entry((pd), (pde), (old), (to), px_dma(to), gen8_pde_encode)
> +
>  /*
>   * PDE TLBs are a pain to invalidate on GEN8+. When we modify
>   * the page table structures, we mark them dirty so that
> @@ -1328,11 +1350,8 @@ static int gen8_ppgtt_alloc_pd(struct i915_address_space *vm,
>                         if (count < GEN8_PTES || intel_vgpu_active(vm->i915))
>                                 gen8_initialize_pt(vm, pt);
>  
> -                       old = cmpxchg(&pd->entry[pde], vm->scratch_pt, pt);
> -                       if (old == vm->scratch_pt) {
> -                               set_pd_entry(pd, pde, pt);
> -                               atomic_inc(&pd->used);
> -                       } else {
> +                       old = swap_pd_entry(pd, pde, vm->scratch_pt, pt);
> +                       if (unlikely(old != vm->scratch_pt)) {
>                                 free_pt(vm, pt);
>                                 pt = old;
>                         }
> @@ -1373,11 +1392,8 @@ static int gen8_ppgtt_alloc_pdp(struct i915_address_space *vm,
>  
>                         init_pd(vm, pd, vm->scratch_pt);
>  
> -                       old = cmpxchg(&pdp->entry[pdpe], vm->scratch_pd, pd);
> -                       if (old == vm->scratch_pd) {
> -                               set_pd_entry(pdp, pdpe, pd);
> -                               atomic_inc(&pdp->used);
> -                       } else {
> +                       old = swap_pd_entry(pdp, pdpe, vm->scratch_pd, pd);
> +                       if (unlikely(old != vm->scratch_pd)) {
>                                 free_pd(vm, pd);
>                                 pd = old;
>                         }
> @@ -1442,10 +1458,8 @@ static int gen8_ppgtt_alloc_4lvl(struct i915_address_space *vm,
>  
>                         init_pd(vm, pdp, vm->scratch_pd);
>  
> -                       old = cmpxchg(&pml4->entry[pml4e], vm->scratch_pdp, pdp);
> -                       if (old == vm->scratch_pdp) {
> -                               set_pd_entry(pml4, pml4e, pdp);
> -                       } else {
> +                       old = swap_pd_entry(pml4, pml4e, vm->scratch_pdp, pdp);
> +                       if (unlikely(old != vm->scratch_pdp)) {
>                                 free_pd(vm, pdp);
>                                 pdp = old;

Otherwise, the only difference between these stanzas is now
vm->scratch[lvl] :)

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris